Just a follow up for Mrs. D and anyone else who saw this post last year:

My son continued to have major and worsening digestive issues until last September when we and the doctors finally determined that an exploratory surgery was necessary. They found he had Meckel's Diverticulum including a mesodiverticular band. (A congenital defect found in about 2% of the population, but is normally asymptomatic.) In his case, it grew very large and twisted around his small intestines causing intermittent obstructions - very similar to your malrotation issue. It was necessary to remove the diverticulum as well as about a foot of his small intestine, but after a somewhat challenging recovery, he no longer has any issues. He can now eat anything a normal 23 year old can, without worrying about horrible consequences.

So in the end, it wasn't a functional or neuropathic issue at all.

BTW, he did use the L-glutamine you recommended prior to his surgery as well as through the recovery process - and it did seem to help him recover faster after his "episodes". So, we do thank you for your suggestion.